My powder scattering problem may just be me. After I get about 10 rounds in, I tend to drift a bit, and it's almost a certainty I will fail to notice when one of the bullets drops, and I'll take a backswing before I notice the bullet is free. Powder flies out the tail of the hammer.

It's a lot better at containing powder even when I backswing with the Lee shell holder, but I still end up getting a bit of powder free flying around my shop. Not a big issue, probably less mess than any time I deprime, let alone when I change/empty my powder dispensers...

Despite so many years doing lab work, I'm terrible about powder management. I'm also very persnickety about powder management. A dozen kernels around the base of my press after a hundred rounds is, "a mess."